Apparatus and method for dispensing particulate material

ABSTRACT

An apparatus capable of dispensing particulate material and a method for accomplishing the dispensing of the material. The apparatus includes a fluid-activated means capable of causing particulate material to be withdrawn from a reservoir at a rate which is substantially proportional to the fluid flow rate in the fluid-activated means. A means for dispensing the particulate material toward an article to be coated is connected to the fluid-activated means through a conduit. A fluid divider has an inlet port connected to a source of compressed fluid. The fluid divider also includes a plurality of outlet ports. One of the outlet ports of the fluid divider is connected to the reservoir to thereby provide the fluid flow which activates the fluidactivated means. Another of the outlet ports of the fluid divider is connected to the conduit to provide a fluid flow in the conduit which assists in the movement of the particulate material in the conduit toward the means which dispenses the material. The fluid divider may be a device which includes a fluid-splitting member which divides the fluid flow at the inlet port among the several outlet ports. The sum of the fluid flows at the outlet ports of the fluid divider is substantially proportional to the fluid flow at the inlet port.

Unite 72] Inventor Richard O. Probst Indianapolis, Ind. [21] Appl. No.829,206 [22] Filed June 2,1969 [45] Patented Dec. 7, I971 [73] AssigneeRansburg Electra-Coating Corp.

Indianapolis, Ind.

[54] APPARATUS AND METHOD FOR DISPENSING PARTICULATE MATERIAL 16 Claims,4 Drawing Figs.

[52] US. Cl 222/193, 137/625. 14 [51] Int. Cl 865g 69/06 [50] Field ofSearch 222/193, 195,485,486; 239/15; l37/625.14, 625.12, 625.33, 625.5

[56] References Cited UNITED STATES PATENTS 2,934,090 4/1960 Kenann etal 137/625.5 2,123,537 7/1938 Marr 222/193 3,251,551 5/1966 Walberg239/15 Primary Examiner-Stanley H. Tollberg At!0rneysMerrill N. Johnson,Harry E. Downer, David H.

Badger and Charles W. Hoffmann ABSTRACT: An apparatus capable ofdispensing particulate material and a method for accomplishing thedispensing ofthe material. The apparatus includes a fluid-activatedmeans capable of causing particulate material to be withdrawn from areservoir at a rate which is substantially proportional to the fluidflow rate in the fluid-activated means. A means for dispensing theparticulate material toward an article to be coated is connected to thefluid-activated means through a conduit. A fluid divider has an inletport connected to a source of compressed fluid. The fluid divider alsoincludes a plurality of outlet ports. One of the outlet ports of thefluid divider is connected to the reservoir to thereby provide the fluidflow which activates the fluid-activated means. Another of the outletports of the fluid divider is connected to the conduit to provide afluid flow in the conduit which assists in the movement of theparticulate material in the conduit toward the means which dispenses thematerial. The fluid divider may be a device which includes afluid-splitting member which divides the fluid flow at the inlet portamong the several outlet ports. The sum of the fluid flows at the outletports of the fluid divider is substantially proportional to the fluidflow at the inlet port.

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1 u u l I I l l I I l I l l l l I l SHEET 1 0F 2 PATENTEB DEC 7197:

INVENTOR RICHARD O. PROBST PATENTEn DEC 7 I971 3525404 sum 2 or z IOI 9593 F g 4 9 INVEN'TOR RICHARD 01'? P'ROBST APPARATUS AND METHOD FORDISPENSING PARTICULATE MATERIAL The present invention relates to adispensing apparatus and, more particularly, to an apparatus capable ofdispensing particulate material and to a fluid-dividing device which maybe used as a component part of the apparatus. In addition, the presentinvention relates to a method for dispensing the particulate material.

Generally, a particulate material-dispensing apparatus is connected to asource of compressed air which serves as the means for activating asuitable air-activated pump. The pump generally includes anopen-throated venturi tube seated in a reservoir containing particulatematerial. As the compressed air flows through the open-throated venturitube, particulate material is caused to be drawn from the reservoir at arate proportional to the rate of flow of the air through the venturitube. The particulate material is entrained in the air and delivered bythe flowing air to a dispensing device such as a handgun. The handguncauses the particulate material to be directed toward a surface of anarticle to be coated with the material.

The movement or rate of flow of the entraining air emitted at the nozzleof the dispensing device should be sufficiently high so as to achieve,among other things, the desired spray pattern, the desired distributionof the particulate material within the spray pattern and a uniform layerof the material on the article. Usually, satisfactory coating of thearticle with the particulate material is accomplished by using a hosehaving an internal diameter of about of an inch and using an airflowthru the air-activated pump of from about 1.5 to about 2.5 standardcubic feet per minute (s.c.f.m.

Generally, the hose has a substantially constant internal diameter so asto assist in providing the proper airflow rate necessary to transportthe entrained material and to minimize the possibility of providingsites at which the particulate material may accumulate. The hose isgenerally satisfactory for its intended purpose as long as the airflowrate within the hose remains above a velocity which discouragesaccumulation of the particulate material along the sidewall of the hose.However, if the flow rate of the material through the hose drops below aminimum velocity due to any one of several factors such as a reductionin airflow below about 1.5 s.c.f.m. in a hose having a 36 inch internaldiameter, the particulate material exhibits a tendency to accumulatealong the sidewall of the hose connected between the reservoir and thedispensing device. During the interval of time the particulate materialis accumulating along the sidewalls of the hose, the amount of materialbeing emitted per unit of time by the dispensing device may be belowthat which is necessary to coat the article within the required timeinterval with a uniform coating of material having a desired thickness.

When a sufficient amount of the particulate material has accumulatedalong the sidewall of the hose, the air pressure behind the accumulatedmaterial may build up sufl'lciently to provide a force adequate to causethe movement of the accumulated mass of particulate material through thehose and out of the nozzle of the dispensing means. Upon release of theaccumulated mass of particulate material, the material again starts toaccumulate along the sidewall of the hose until sufficient force isprovided to move the mass of accumulated particulate material throughand out of the hose. The release of the mass of accumulated material maybe referred to as puffing." The accumulation and release of accumulatedparticulate material is cyclical. As a result of substantiallyinstantaneous release of the accumulated mass of particulate materialfrom the dispensing means, undesirable amounts of the material may bedeposited onto the article. In addition, pufling" can cause localizedheavy coating of material on the article and thus the coating tends tobe undesirably nonuniform.

A reduction in the magnitude of the puffing" problem may be realized byusing a hose having a smaller internal diameter when the flow rate ofthe air is reduced. However, an operator may experience an inconvenienceby shutting down" the operation of the equipment in order to remove thehose and substitute for it a hose having a smaller internal diameter.

Therefore, it is an object of the present invention to provide a meansand a method which overcome the above-stated problems.

Another object of the present invention is to provide an apparatuscapable of dispensing particulate material entrained in a fluid whicheliminates the necessity for changing from one hose diameter to adifferent hose diameter as the flow rate of the material through thehose is altered.

A further object of the present invention is to provide an apparatuscapable of dispensing particulate material entrained in a fluid, thefluid having a substantially uniform flow rate at the point where thematerial is dispensed from the apparatus.

Another object of the present invention is to provide an apparatuscapable of dispensing variable amounts of particulate material entrainedin a gaseous medium, the gaseous medium having a substantially uniformflow rate at the point where the material is dispensed from theapparatus.

Yet another object of the present invention is to provide an apparatusfor dispensing particulate material which is capable of depositing asubstantially uniform layer of the material onto an article which may bepassed by the dispensing device at a variable rate of speed.

Yet still another object of the present invention is to provide aparticulate-dispensing apparatus including a fluid divider which assistsin the movement of the material in a conduit towards a means fordispensing the material.

A further object of the present invention is to provide an apparatuscapable of dispensing particulate material which is economical tomanufacture.

Another object of the present invention is to provide means for dividinga fluid flow input into a plurality of fluid flow outputs, the sum ofthe fluid flow outputs of the means being substantially equal to thefluid flow input to the means.

A further object of the present invention is to provide a means having afluid flow input and a plurality of fluid flow outputs, a fluid flowinput to the means resulting in at least one fluid output.

A further object of the present invention is to provide a method fortransporting particulate material to a particulate material-dispensingdevice wherein the fluid flow rate at the dispensing device issubstantially constant with variable amounts of particulate materialentrained in the fluid flow.

With the aforementioned objects enumerated, other objects will beapparent from reading the following description and the appended claims.

In the drawings:

FIG. l is a schematic view of the present invention;

FIG. 2 is a partial cross-sectional view of a means for dividing a fluidflow input into a plurality of fluid flow outputs;

FIG. 3 is a partial cross-sectional view of an embodiment of the meansfor dividing the fluid flow into a plurality of fluid flow outputs; and

FIG. 4 is a schematic view of an embodiment of the present invention.

Generally speaking, the present invention relates to a particulatematerial-dispensing apparatus and method which substantially eliminatespufi'lng" of the material and to a means used as a component part of theapparatus which divides a fluid flow input into a plurality of fluidflow outputs.

The apparatus is capable of dispensing variable amounts of particulatematerial entrained in a fluid medium wherein the fluid medium has asubstantially uniform flow rate under substantially all conditions atthe point in the apparatus where the material is dispensed. Theapparatus includes a fluid-activated means capable of causing theparticulate material to be drawn from a particulate material reservoirat a rate substantially proportional to the fluid flow rate in thefluid-activated means. A conduit is used to connect the reservoir to adevice which dispenses the particulate material. The fluid divider ofthe apparatus has an inlet port connected to a source of compressedfluid. The fluid divider includes at least one outlet port connected tothe fluid-activated means so as to provide a fluid flow in thefluid-activated means and at least one other outlet port connected tothe conduit so as to provide a fluid flow in the conduit which assistsin the movement of the fluid-entrained particulate material toward themeans which dispenses the material. The sum of the fluid flows at theoutputs of the fluid divider is substantially equal to the fluid flow atthe input of the fluid divider thereby providing a fluid flow rate inthe conduit between the fluid-activated means and the dispensing meanswhich is substantially uniform and a fluid flow rate in thefluid-activated means which may be varied so as to withdraw variableamounts of the material from the reservoir without harmfully effectingthe flow rate of the fluid through the conduit.

The method of the present invention generally relates to dividing afluid flow input into a plurality of fluid flow outputs, which outputsare substantially equal in total to the input. The divided fluid is usedto provide a fluid flow rate at the dispensing device which issubstantially uniform and which is capable of providing variable butcontrolled amounts of particulate material entrained in the fluid flow.

Referring now to FIG. 1 of the drawing, the apparatus of the presentinvention, capable of dispensing a particulate material, is indicated bythe reference numeral 10. The apparatus includes means 11 which dividesa fluid flow input into a plurality of fluid flow outputs, a fluidizedbed 12 which includes a reservoir 27 for particulate material 13 andincludes a suitable fluid activated pump 14 which draws the material 13from the bed 12, and a dispensing device 15 which dispenses the material13 toward an article (not shown) to be coated with the material 13.

The input port of fluid divider 11 may be connected to any suitablesource 16 of compressed fluid through a suitable fluid conduit 19. Thesource 16 of compressed fluid may include suitable pressure-regulatingdevices 17 and 17' which are intended to compensate for variations inthe fluid flow rate supplied by a suitable fluid compressor 18. Thefluid supplied by the fluid source 16 may be any suitable medium whichis capable of being easily compressed and which is capable of entrainingthe particulate material 13. A suitable fluid is a gas such as air andthe like.

The fluid divider 11 may include any suitable means which is capable ofdividing the compressed fluid supplied thereto by the source 16 into atleast two fluid outputs. The sum of the fluid flow rate at the outputsof the fluid divider 11 is substantially equal to the fluid flow rate atthe input to the fluid divider. In addition, the fluid divider 11 mayinclude a means (not shown in FIG. 1) which is capable of varying oradjusting the flow rate of compressed air from each of the output ports.The structure of the fluid divider 11 and its operation will bediscussed herein later.

The fluid-activated pump 14 of the fluidized bed 12 is connected to oneof the outlet ports of the fluid divider 11 by way of conduit 21. Thefluidized bed 12 further includes a particulate material reservoir 27having air chamber 29 which may be equipped with an air-distributingdevice 24, an agitator 25 and a membrane 26 which permits fluidizing airto pass upwardly therethrough and which prevents the particulatematerial 13 from passing downwardly therethrough. The air-distributingdevice 24 may be connected to the pressure-regulating device 17' ofsource 16 of compressed fluid by any suitable conduit such as hose 28.The air-distributing device 24, the membrane 26 and the agitator 25cooperate to fluidize the particulate material 13. The membrane 26supports the fluidized particulate material 13 and maintains thematerial separate from the air chamber 29. The fluid-activated pump 14may traverse the length of the bed 12 above the air chamber 29 and inthe fluidized particulated material 13. The fluid-activated means 14 mayinclude an open-throated venturi tube (not shown). Although the opening23 cooperatively associated with the venturi tube may be facing upwardlyas illustrated in FIG. 1, it is understood that the openingcooperatively associated with the venturi tube may be faced to a side ofthe fluidized bed or faced down as desired. The movement of air from thesource 16 through the open-throated venturi tube causes the fluidizedparticulate material 13 to be drawn into the open-throated venturi tube.In lieu of the agitator 25, the fluidized bed 12 may be equipped with avibrating member (not shown). The vibrating member tends to provide auniform distribution of particulate material 13 to the open-throatedventuri tube.

A suitable conduit such as a hose 22 may be used to carry theparticulate material 13 from the open-throated venturi tube of the fluidpump 14 to dispensing device 15.

The dispensing device 15 may be any suitable electrostatic dispensingdevice such as a handgun capable of emitting and imparting anelectrostatic charge to the particulate material 13. A suitabledispensing device 15 is an electrostatic powder dispensing handguncarrying the nomenclature Assembly No. 322/8446 sold by the RansburgElectro'Coau'ng Corp. An electrical power supply is connected to theelectrostatic handgun and should be capable of supplying up to about90,000 volts DC at a current of up to about 200 microamperes to the handgun. A suitable power supply is Power Supply Assembly No. 231/8910 soldby the Ransburg Electro-Coating Corp.

Another outlet port of the fluid divider 11 is connected to the conduit22 at a location downstream from the outlet orifice of thefluid-activated pump 14 by means of conduit 20. The flow rate of airthrough conduit 20 to the conduit 22 assists in the movement ofparticulate material 13 in conduit 22 toward the dispensing device 15.it is seen that a portion of compressed air emitted by source 16 isdiverted from the fluid-activated pump 14 to a location which is betweenthe dispensing device 15 and the pump 14. Generally, the airflow rate inthe conduit 22 from the point where the conduit 20 is connected to theconduit 22 to the dispensing device 15 is substantially constant andequal to the sum of the airflow rates of the pump 14 and the conduit 20.However, it is to be understood that during the operation of thefluid-activated pump 14, the venturi tube may cause additional air to bedrawn thereinto, thereby increasing the airflow rate in conduit 22slightly above the sum of the airflow rates at the outlet ports of thefluid divider 11. l

The present invention contemplates varying or adjusting the flow rate ofair through the venturi tube as desired to thereby vary the amount ofparticulate material 13 withdrawn from bed 12 without materiallyaltering the airflow in conduit 22. Therefore, large or small quantitiesof the particulate material 13 may be withdrawn per unit of time frombed 12 without materially altering the total fluid flow rate throughconduit 22. It is seen that the airflow rate in conduit 22 issubstantially constant under nearly all conditions thereby obviating thenecessity for disconnecting conduit 22 from the fluid-activated pump 14and the dispensing means 15 to alter the diameter of the conduit 22 inan attempt to minimize the possibility of particulate material 13agglomerating or accumulating within conduit 22 to thereby reduce thepossibility of puffing" of the material 13.

The point at which the hose 20 joins the hose 22 should be as close tothe outlet orifice of the fluid-activated means 14 as is physicallypossible. So locating the junction point minimizes the possibility ofthe particulate material 13 accumulating at a site between the outletorifice of the fluid-activated means and the point at which hose 20joins hose 22.

The particulate material 13 may be any dry, powdery substance which iscapable of being fluidized, which is capable of being entrained in afluid medium such as air and which is capable of accepting anelectrostatic charge. Suitable powders are thennoplastic powders such ascellulose acetate butyrate, chlorinated polyether, polyester,polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethyleneand the like; thermosetting resins such as epoxy and the like; and otherpowdery substances such as commercial talc, flour, glass, zinc stearate,starch, vitreous enamel and the like.

Referring now to FIG. 2 of the drawing, the fluid divider of the presentinvention is indicated by the reference number ill. As dimussedhereinbefore, the fluid divider llll provides a means for dividing thefluid supplied thereto by the source 16 of compressed air. The fluiddivider ill includes a hollow, generally cylindrical housing 41 havingat least one inlet port 511 and at least two outlet ports 52 and 53. Thehousing 411 may be fabricated from any suitable material which providesgood wear and is available at reasonable cost. Suitable materials fromwhich the housing 41 may be fabricated are brass, aluminum, stainlesssteel, reinforced plastic and the like. 0f the several materials fromwhich the housing 41 may be fabricated aluminum is the preferredmetallic material.

The diameter of the inlet port 511 of the housing Ill and the diametersof the outlet ports 52 and 53 are illustrated in the drawing as beingsubstantially the same thereby providing substantially equal-area inletand outlet ports. it is thought that the diameter of any one or all theports need not be substantially the same. in addition, it is recognizedthat the housing may have a configuration other than the configurationillustrated in lFlG. 2. For example, the housing 111 may have a "U"shaped configuration, T" shaped configuration and the like.

As shown in H6. 2 a displaceable, flow-splitting member 46 is locatedadjacent the inlet port 51 and between the outlet ports 52 and 53. Theflow-splitting member 46 may include base-to-base coupledfrustoconical-shaped members 47 and 48. Each of the members 47 and 48possess such a shape and diameter so as to engage or disengage withchamfers 43 and 44 respectively thereby encouraging, as the case may be,the airflow from the inlet port 51 to outlet port 52 or to outlet port53. it is noted that the fluid divider 1 ll allows fluid to flow from atleast one of the outlet ports under all operating conditions. Forexample, substantially all of the compressed air present at inlet port511 will flow through outlet port 52 if the frustoconical shaped member48 is engaged with chamfer 44 so as to discourage compressed airflowthrough outlet port 53. The flow-splitting member 46 should befabricated from a material similar to the material from which thehousing 41 is fabricated to minimize the occurrence of galvaniccorrosion.

The housing of the fluid divider ll may include seats 43 and 44 providedin the housing 41. The seats 43 and 44 may be chamfered at an anglegreater than or less than the angle of the frustoconical membercooperatively associated therewith. It should be seen that it is notnecessary for either of the frustoconical members 47 and 48 to tightlyseal with their respective chamfers 43 and 44. it is thought that it isonly necessary that the frustoconical members and the chamfers cooperatein such a manner so aS to prevent a substantial flow of compressed airtherebetween. However, it is recognized that if an airtight seal isdesirable, a suitable seal may be provided between the frustoconicalmember and its cooperatively associated chamfer, if desired.

Displacement of the frustoconical members 47 and 48 of theflow-splitting member 46 may be accomplished by any number of differenttechniques. One technique of displacing the member 46 is by rotatingshaft 49 connected to the flow splitting member 46 by rotating knurledknob 50 so as to turn shaft 49 into or out of aperture 54 formed in thehousing 411. lt is seen that displacement of shaft 49 causeslongitudinal displacement of the flow-splitting member 46. Longitudinaldisplacement of the flow-splitting member 46 causes the air flow at theinlet port 511 to be diverted to outlet ports 52 and 53 or only tooutlet port 52 or only to outlet port 53 depending on the location ofthe transverse axis of the fluid flow-splitting member 46 with respectto the axis of the inlet port 51. Positioning the frustoconicalflow-splitting member 46 within the bore 55 of the housing 41. as shownin FIG. 2, causes a reduced amount of compressed air to flow out ofoutlet port 53 as compared with the amount of compressed air flowing outof outlet port 52. Displacement of the flow-splitting member 46 to aposition where the transverse axis thereof substantially coincides withthe axis of the input orifice 511, results in a condition where theamount of airflow rate from both outlet ports 52 and 53 aresubstantially equal assuming that each of the Outlet ports havesubstantially equal-area outlets. if the transverse axis of theflow-splitting member 46 is displaced slightly from the axis of theinput port 511 toward the outlet port 52, the airflow ate at outlet port53 should be greater than the airflow rate at outlet port 52 assuming,as shown in FIG. 2, that the outlet ports 52 and 53 are of equal-area.The airflow through outlet port 53 is greater than the airflow throughoutlet port 52 since impedance to airflow through port 52 is greaterthan the impedance to airflow through port 53. if the flow-splittingmember 46 is displaced to a position where the sidewall of thefrustoconical member 47 engages with the chamfer 43 formed in thehousing 411, the impedance to the airflow through port 52 is nearlyinfinite and, therefore, substantially all of the compressed air willflow from inlet port 511 to outlet port 53. Displacement of thetransverse axis of the flow-splitting member 46 to the right of the axisof the inlet orifice 51 results in more compressed air flowing throughoutlet port 52 than through outlet port 53. Displacement of thefrustoconical member 43 of the flow-splitting member 46 to a position ofengagement with the chamfer 44 of the housing 4! encouragessubstantially all of the compressed air flowing from the source ofcompressed air l6 to flow from outlet port 52.

An initial adjustment of each of the frustoconical members 47 and 45with respect to its cooperatively associated chamfer may be desirable sothat the cooperative relationship between the frustoconical member andits chamfer provides the desired restriction for any given position ofthe frustoconical member with respect to its cooperatively associatedchamfer. To accomplish the adjustment, frustoconical member 48 may berotated independently of member 47 to thereby longitudinally displacemember 48 with respect to member 47 until the desired relationshipbetween the member 48 and its cooperatively associated chamfer 44 isachieved. Member 47 and chamfer 43 would have its cooperativerelationship established by turning shaft 49 into or out of the aperture54 prior to the adjustment of member 46 with respect to itscooperatively associated chamfer. It is understood that the position ofmember 47 with respect to chamfer 43 should remain unaltered during theinitial positioning of member 48 with respect to their cooperativelyassociated chamfers, the members will move together by rotating shaft49.

The configuration of one or each of the members 47 and 48 of theflow-splitting member 46 may be shaped different from the shapeillustrated in FIG. 2. For example, the member 46 and/or the member 47may have a convexed side configuration, a concaved side configurationand the like in lieu of the side configuration illustrated. The chamfers43 and 44 provided in the housing 41 may be similarily altered so as tofit with the members 46 and 47 when the members engage therewith.

With the structural disclosure in mind and by continued reference toFIGS. 1 and 2 of the drawing, the following analysis of the operation ofthe present invention will further serve to amplify the novelty of thepresent invention.

Connecting the source 16 of compressed air to the inlet port 511 of thefluid divider llll encourages compressed air to flow from the source 16through the inlet port 51 to the outlet ports 52 and 53 of the fluiddivider. Assuming that the flow-splitting member 46 has its transverseaxis substantially coincident with the axis of the inlet orifice 511,the impedance presented to the airflow to each port is substantiallyequal, therefore, the airflow rate through outlet port 52 and outletport 53 is substantially equal. About one-half of the compressed airfrom source 16 flows to fluid-activated pump 14 so as to draw theparticulate material 113) through the open-throated venturi tube 29 andcause it to flow entrained in air into conduit 22. The rate at which thematerial 13 is drawn from the fluidized bed 112 by the fluid-activatedpump 14 is proportional to the flow rate of the compressed air throughthe venturi tube of the fluid-activated pump. The remainder of thecompressed air is caused to flow directly to hose 22. Hose 22 isdownstream from the fluid-activated pump 114. it should be seen,however, that substantially all of the compressed air supplied by thesource 16 to the apparatus 10 is transferred to dispensing devicethrough hose 22.

An operator may vary the amount of material 13 drawn from the fluidizedbed 12 by directing greater or lesser amounts of airflow rates throughthe fluid-activated pump 14. The airflow rate delivered to thefluid-activated pump 14 may be varied by varying the position of theflow-splitting member 46 of flow divider 11 with respect to the outletports 52 and 53. For example, if a greater amount of particulatematerial 13 is to be drawn from the fluidized bed 12 and deposited ontoan article, a greater portion of the compressed air is caused to flow tothe pump 14, that is the airflow rate to the pump 14 is increased, and alesser amount of compressed air is shunted to the hose 22, that is theairflow rate to the hose 22 through line is decreased. If the amount ofparticulate material 13 to be deposited on the article is required to beless, the amount of compressed air caused to flow to the fluid-activatedpump 14 is reduced thereby reducing the amount of particulate material13 drawn from the fluidized bed 12; however, it is seen the flow rate ofthe compressed air in hose 22 remains substantially independent ofvariations in the flow rate at pump 14.

The present invention substantially reduces the possibility ofaccumulation of the particulate material 13 within the hose 22 since theairflow rate within hose 22 is above a minimum flow rate regardless ofthe amount of particulate material 13 drawn from the fluidized bed 12 bythe fluid-activated pump 14. If a higher dispensing rate of particulatematerial 13 is desired, the flow-splitting member may be moved to aposition whereby the outlet port 52 connected to the fluid-activatedpump 14 is supplied with an increased flow rate of air. The increasedflow rate of air through the venturi tube causes a greater amount ofparticulate material 13 to be drawn from the fluidized bed 12; however,the airflow rate within substantially the entire hose 22 remainssubstantially constant thereby significantly reducing the possibility ofpuffing" of the particulate material 13 as it is emitted by thedispensing device 15. If a lesser amount of particulate material 13 isdesired to be dispensed by device 15, the flow-splitting member is movedto a position so that the airflow rate through the venturi tube of thefluid activated pump 14 is reduced so as to draw less particulatematerial 13 from the fluidized bed 12 and so that the airflow ratethrough the hose 20 is increased. It should be noted, however, that theamount of airflow rate within hose 22, downstream from thefluid-activated pump 14, remains substantially constant therebyminimizing the possibility of puffing" of the particulate material 13 asit is delivered to the article to be coated.

Referring now to FIG. 3 of the drawing, an embodiment of the fluiddivider of the present invention is indicated by the reference number81. As discussed hereinbefore, the fluid divider provides a means fordividing the fluid supplied thereto by the source of compressed air suchas source 16. The fluid divider 81 includes a hollow, generally squarehousing 82 made up of housing half 101 and housing half 102 fixedlyretained together by any suitable coupling means (not shown) such asbolts and the like. The housing 82 may be fabricated from any suitablematerial which provides good wear and is available at reasonable cost.Suitable materials from which the housing 82 may be fabricated arebrass, aluminum, stainless steel, reinforced plastic and the like. Ofthe several materials from which the housing 41 may be fabricatedaluminum is the preferred metallic material.

The housing half 102 includes at least one inlet port 83 and at leasttwo outlet ports 84 and 85. The diameter of the inlet port 83 of thehousing 82 and the diameters of the outlet ports 84 and 85 areillustrated in the drawing as being substantially the same therebyproviding substantially equal-area inlet and outlet ports. It is thoughtthat the diameter of any one or all the ports need not be substantiallythe same.

A displaceable, flow-splitting member 86 is located adjacent the inletport 83 and between the outlet ports 84 and 85. The flow-splittingmember 86 may include base-to-base coupled frustoconical-shaped members87 and 88. It should be recognized that members 87 and 88 may have ashape other than frustoconical such as conical and the like. Each of themembers 87 and 88 possess such as shape and diameter so as to engage ordisengage with chamfers 89 and 90 respectively thereby encouraging ordiscouraging, as the case may be, the airflow from the inlet port 83 tooutlet port 84 or to outlet port 85. It is noted that the fluid divider81 allows fluid to flow from at least one of the outlet ports under alloperating conditions. For example, substantially all of the compressedair present at inlet port 83 will flow through outlet port 85 if thefrustoconical-shaped member 87 is engaged with chamfer 89, asillustrated in H6. 3, so as to discourage compressed airflow throughoutlet port 84. The flow-splitting member 86 should be fabricated from amaterial similar to the material from which the housing 82 is fabricatedto minimize the occurrence of galvanic corrosion.

The housing 82 of the fluid divider 81 may include seats 89 and 90. Theseats 89 and may be chamfered at an angle greater than or less than theangle of the frustoconical member cooperatively associated therewith. Itshould be seen that it is not necessary for either of the frustoconicalmembers 87 and 88 to tightly seal with their respective chamfers 89 and90. it is thought that it is only necessary that the frustoconicalmembers and the chamfers cooperate in such a manner so as to prevent asubstantial flow of compressed air therebetween. However, it isrecognized that if an airtight seal is desirable, a suitable seal may beprovided between the frustoconical member and its cooperativelyassociated chamfer, if desired.

Displacement of the frustoconical members 87 and 88 of theflow-splitting member 86 may be accomplished by any number of differenttechniques. One technique of displacing the member 86 may beaccomplished by rotating shaft 91 connected to the flow-splitting member86 through threaded block 92 and pin 93, carried by block 92 and fixedlyconnected to flow-splitting member 86, by rotating knurled knob 94 so asto turn shaft 91 in recess 95 formed in the housing 82. Shaft 91 andblock 92 are carried in housing half 101. It is seen that rotating shaft91 causes longitudinal displacement of block 92 and displacement of pin93 thereby causing longitudinal displacement of the flow-splittingmember 86. Longitudinal displacement of the flow-splitting member 86causes the airflow at'the inlet port 83 to be diverted to outlet ports84 and 85 or only to outlet port 83 or only to outlet port 84 dependingon the location of the transverse axis of the fluid flow-splittingmember 86 with respect to the axis of the inlet port 83. Positioning thefrustoconical flow-splitting member 86 within the bore of the housing 82as shown in FIG. 3, discourages compressed air from flowing out of theoutlet port 84 and encourages substantially all of the compressed air toflow out of outlet port 85. Displacement of the flow-splitting member 86to a position where the transverse axis thereof substantially coincideswith the axis of the input orifice 83, results in a condition where theamount of airflow rate from both outlet ports 84 and 85 aresubstantially equal assuming that each of the outlet ports havesubstantially equal-area outlets. If the transverse axis of theflow-splitting member 86 is displaced slightly from the axis of theinput port 83 toward the outlet port 85, the airflow rate at outlet port84 should be greater than the airflow rate at outlet port 85 assuming,as shown in FIG. 3, that the outlet port 84 and 85 are of equal-area.The airflow through outlet port 84 is greater than the airflow throughoutlet port 85 since impedance to airflow through port 84 is greaterthan the impedance to airflow through port 85. lf the flow-splittingmember 86 is displaced to a position where the sidewall of thefrustoconical member 88 engages with the chamfer 90, the impedance tothe airflow through port 85 is nearly infinite and, therefore,substantially all of the compressed air will flow from inlet port 83 tooutlet port 84.

The threaded block 92 may be cylindrical in cross section. The recess 95in which the threaded block 92 is slidably displaced should have thesame general configuration as the peripheral contour of the block tothereby facilitate displacement of the block therein. It is seen thatthe axial aperture 96 of the block 92 is threaded so as to mate with thethreads formed on the shaft 91.

Rotational displacement of shaft 91 does not result in longitudinaldisplacement thereof but rotational displacement of the shaft doesresult in longitudinal displacement of the block 92 in the cylindricalrecess 95. The amount of longitudinal displacement of the block 92within recess 95 may be governed by, among other things, the number ofthreads per unit length of the shaft 91 and of the block 92.

A pin 93 may be carried by block 92 and fixedly attached toflow-splitting member 86 at an angle which is substantiallyperpendicular to the longitudinal axis of the block. One extremity ofthe pin 93 may be threaded. A threaded aperture 93 may be formed in theflow-splitting member 86 which substantially coincides with thetransverse axis of the flow-splitting member. The threaded extremity ofthe pin mates with the threaded aperture 93 of the flow-splitting member66. It is seen that rotational displacement of shaft 91 causeslongitudinal displacement of block 92 and displacement of the pin 93 andhence longitudinal displacement of the flow-splitting member 86. The pin93 may be slidably displaced in guide slot 79 provided by thecooperative relationship of housing half 1101 and housing half 102. Oneof the several functions of the slot is to substantially prevent the pinand the block 92 from rotating with the shaft 91 as the shaft isrotatably displaced. The flow-splitting member 86 is indirectly drivenby rotation of shaft 91 whereas in the embodiment shown in H0. 2,rotation of shaft 49 directly drives flow-splitting member 46.

An initial adjustment of the charnfer 90 with respect to theflow-splitting member 86 may be desirable so that the cooperativerelationship between the flow-splitting member 86 and its cooperativelyassociated charnfer provides the desired restriction for any givenposition of the flow-splitting member with respect to its cooperativelyassociated charnfer. To accomplish the adjustment, plug 99 sealing oneend of bore 100 may be rotated to thereby longitudinally move plug 99with respect to the flow-splitting member 86 until the desiredrelationship between the frustoconical member 88 and charnfer 90 isachieved. Frustoconical member 87 and charnfer 89 would have itscooperative relationship established by rotating shaft 91 prior to theadjustment of member 88 with respect to its cooperatively associatedcharnfer 90. lt is understood that the position of member 87 withrespect to charnfer 89 would remain unaltered during the initialpositioning of member 88 with respect to charnfer 96.

The configuration of one or each of the members 87 and 88 of theflow-splitting member 86 may be shaped different from the shapeillustrated in FIG. 3. For example, the member 86 and/or the member 87may have a convexed side configuration, a concaved side configurationand the like in lieu of the side configuration illustrated. The chamfers89 and 91) provided in the housing 81 may be similarily altered so as tofit with the members 39 and 90 when the members engage therewith.

Referring to F16. 4 of the drawing, an embodiment of the presentinvention is illustrated which automatically regulates the airflow ratein a portion of the system. The embodiment is indicated by the referencenumeral 10'. The apparatus 10' includes means 34 which automaticallydivides a fluid flow input from source 16 of compressed air into aplurality of fluid flow outputs, a fluidized bed 12 which includes areservoir 27 retaining particulate material 13 and includes a suitablefluidactivated pump 14 which draws the material 13 from the bed 12, anda dispensing device 15 which dispenses the material 13 toward an article(not shown) to be coated with the material 13.

Several of the means which are used in FIG. 1 may also be adaptable foruse with the embodiment illustrated in FIG. 4. Where the meansillustrated in FIG. 1 have been used in FIG. 4, the same referencenumerals have been used to indicate these means. For example, thefluidized bed 12 of MG. 1 may be used in the embodiment of FIG. 4. Thestructure and function of each of the means illustrated in F16. 4 whichcarries the same reference numeral as the means illustrated in FIG. 1 isidentical to the means illustrated in FIG. 1.

The automatic fluid divider 34, connected to source 16 of compressed airby means of conduit 19, may include a means which is capable ofautomatically dividing the compressed fluid supplied thereto by thesource 16 into at least two fluid outputs in response to a controlsignal. The control signal is supplied to the fluid divider by way ofconduit 66. A particular pressure of the control signal may correspondto an event such as a particular rate of speed of a conveyor (notshown). The pressure of the control signal may be varied so as tocorrespond to the varying rate of speed of the conveyor.

In the embodiment shown in FIG. 4, the flow divider 34 includes at leasta pair of pressure regulators 31 and 32. Regulator 31 includes a controlport 60, an inlet port 64 and an outlet port 61. Regulator 32 includes acontrol port 62, an inlet port 65 and an outlet port 63. The sum of thefluid flow rates at the output ports 61 and 63 of the automatic fluiddivider 34 is substantially equal to the fluid flow at the input port tothe automatic fluid divider.

The operation of pressure regulators 31 and 32 is controlled by themagnitude of the pressure of the control signal present at control ports60 and 62 of the regulators. The control signal is provided by controlsignal source 64 which is connected to control ports 611 and 62.Assuming that no control signal appears at control port 60 of thepressure regulator 31, regulator 31 is biased to a closed" position sothat fluid from source 16 connected to the inlet port 64 of regulator 31is not permitted to flow therethrough. When a control signal is causedto appear at control port 60 by the activation of source 64 theregulator 31 is biased to an -opcn" position. The amount of compressedair from source 16 which is permitted to flow through regulator 31 isproportional to the degree that regulator 31 is biased open." The fluidflow rate through pressure regulator 31 from source 16 connected toregulator 31 is proportional to the magnitude of pressure of the controlsignal present at control port 60 of the regulator. Assuming that nocontrol signal from source 64 appears at control port 62 of pressureregulator 32, the pressure regulator is biased to the full open positioncausing a fluid flow at output port 63 from the source 16 through inletport 65 of the regulator. The appearance of a control signal at controlport 62 causes the fluid flow at outlet port 63 to decrease inproportion to the magnitude of the pressure of the control signalprovided by source 64.

As illustrated in FIG. 4 of the drawing, a suitable conduit 2 connectsthe output port 63 of the pressure regulator 32 to the conduit 22 at ajunction just downstream from the fluid activated pump 14. it is seenthat regulator 32 and conduit 20 cooperate to shunt the air flowingtherethrough from the source 16 around the fluidized bed to hose 22. Asuitable conduit 21 connects the output of pressure regulator 31 to theinlet of the fluid-activated pump 14. The regulator 31 is used toregulate the airflow rate through the fluid-activated pump 14 andthereby regulate the rate at which the particulate material 13 is drawnfrom the reservoir 27 of the fluidized bed Hose 22 is used to carry theparticulate material 13 from the open-throated venturi tube of the fluidpump 14 to dispensing device 15.

The control signal at control ports 60 and 62 of pressure regulator 31and of pressure regulator 32 respectively are derived from any suitablesource 64 capable of generating a control signal in response to theoccurrence of an event. The source 64 may provide a control signalhaving a pressure magnitude which relates to an event such as a processfunction. For example, the control signal may be initiated by a suitablesensor (not shown) which is capable of acting on the source 64 so as tocause the source 64 to provide a control signal having a pressureproportional to the event such as the speed of a conveyor (not shown)carrying articles (not shown) to be coated past the'dispensing device15. The parameters of the system may be established so that a stationaryconveyor does not activate the source 64. A deactivated source 64 may beprogrammed so as not to provide a control signal thereby causingpressure regulator 31 to be biased to the closed" position, that ispreventing fluid flow therethrough from source 16 and causing pressureregulator 32 biased to an open" position, that is permittingsubstantially all of the compressed air of the source 16 to flowtherethrough thereby shunting the compressed air of source 16 around thepump 14 in fluidized bed 12. Since the compressed air of source 16 isshunted around the fluid-activated pump 14, no particulate material iscaused to be delivered to spray gun 16. Causing an event to occur whichactivates the sensor (not shown) connected to source 64, such asactivating the conveyor, source 64 is caused to generate a controlsignal which is proportional to the rate of displacement of theconveyor.

The control signal activates the pressure regulator 31 thereby causingcompressed air from source 16 to flow therethrough. The control signalalso causes the regulator to reduce the amount of compressed air whichflows therethrough from source 16. The increase in airflow rate flowstherethrough from source 16 through regulator 31 is proportioned to theairflow rate through regulator 32 thereby dividing the flow fromcompressed air source 16 between conduits 21 and 22. It is seen that asthe airflow rate through the fluid-activated pump 14 is increased, agreater amount of particulate material will be drawn from the fluidizedbed 12, and delivered to the spray gun 15. Thus, the output of the gunmay be varied according to the speed of the conveyor to maintain aconstant coating thickness on the parts to be coated.

A suitable detachable hose union means (not shown) may be used toconnect the hose from the fluid divider and the hose of the fluidizedbed to the hose 22 connected to the dispensing device.

The present invention is not intended to be limited by the disclosuretherein, changes and modifications may be made by those skilled in theart without departing from the spirit and scope of the presentinvention. Such modifications are considered to be within the purviewand scope of the invention.

lclaim:

1. An apparatus capable of dispensing particulate material comprising,

a bed containing particulate material,

a fluid-activated means capable of causing the particulate material tobe drawn from the bed at a rate substantially proportional to the fluidflow rate in the fluid-activated means,

means for dispensing the particulate material drawn from the bed,

a conduit connecting the fluid-activated means to the means fordispensing the particulate material, and

a fluid divider having an inlet port connected to a source of fluidunder an elevated pressure and having a plurality of outlet ports, oneof the outlet ports connected to the fluid-activated means providing thefluid flow in the fluidactivated means, another of the outlet portsconnected to the conduit to provide a fluid flow in the conduit whichassists in the movement of the particulate material in the conduittoward the means for dispensing the particulate material, and the fluiddivider including means activated by a fluid control signal therebyregulating the flow of fluid from at least one of the outlet ports ofthe fluid divider so that the sum of the fluid flows at the outlet portsof the fluid divider is substantially proportional to the fluid flow atthe inlet port of the fluid divider.

2. The apparatus as claimed in claim 1 wherein the fluid dividerincludes a plurality of fluid regulators capable of adjustablyregulating the fluid flow rate supplied to the fluid-activated means andto the other outlet.

3. The apparatus as claimed in claim 2 wherein at least one of the fluidregulators is activated by the control signal to thereby adjustablyregulate the fluid flow rate.

4. The apparatus as claimed in claim 1, wherein the particulate materialincludes a powdery substance capable of being electrostatically chargedand wherein the dispensing means includes an electrostatic spray guncapable of electrostatically charging the powdery substance.

5. The apparatus as claimed in claim 4, wherein the fluid-activatedmeans includes a fluidized bed containing the powdery substance and afluid-actuated pump which draws the powdery substances from thefluidized bed at a rate proportional to the fluid flow rate through thepump.

6. A method for dispensing particulate material comprising dividing afluid flow into a plurality of fluid flow outputs by means of a fluiddivider activated by a fluid control signal thereby regulating the flowof fluid from the fluid divider,

supplying one of the fluid flow outputs to a fluid-actuated meanscapable of drawing particulate material from a bed at a rateproportional to the fluid flow rate in the fluid-activated means, and

combining the fluid flow rates from the fluid-activated means and fromanother of the fluid flow outputs in a conduit connected to a dispensingmeans whereby the fluid flow rate supplied to the dispensing means issubstantially constant.

7. In an apparatus for dispensing particulate material, means fordividing a gaseous input into a plurality of gaseous outputs the sum ofwhich is substantially equal to the gaseous input to the means, one ofthe gaseous outputs is connected to a particulate material-dispensingmeans and other of the gaseous outputs is connected to the dispensingmeans through a source of particulate material, the dispensing meanshaving a substantially constant gaseous flow therethrough that issubstantially independent of the particulate material dispensed wherebyaccumulation of particulate material in the apparatus is discouraged,the means for dividing the gaseous flow comprising a body including aninlet port and a plurality of outlet ports connected by a bore, theinlet port adapted to be connected to a gaseous medium source, theoutlet ports connected to the particulate material dispensing means, and

a displaceable gaseous flow-splitting member in the bore of the bodyadjacent the outlet ports, the gaseous flowsplitting member displaceabletoward one of the outlet ports and away from the remaining outlet portsthereby providing gaseous outputs the sum of which is substantiallyequal to the gaseous input.

8. The means as claimed in claim 7, wherein the gaseous flow-splittingmember includes surfaces which encourage fluid flow toward the outletports.

9. The means as claimed in claim 8, wherein the gaseous fluid-splittingmember includes a plurality of frustoconical members having adjacentbases.

10. The means as claimed in claim 9, wherein each of the frustoconicalmembers have substantially the same dimensions and substantially thesame taper angle and each of the outlet ports have substantially equalarea openings adjacent the frustoconical members.

11. The means as claimed in claim 10, wherein the outlet ports are twooutlet ports spaced from each other and the openings thereof aresubstantially coaxial.

12. The means as claimed in claim 11, wherein the axis of the inlet portis substantially perpendicular to the axis of the outlet ports.

13. An apparatus for dispensing particulate material comprising a bedcontaining particulate material,

a fluid-activated means in the bed for causing the particulate materialto be drawn from the bed at a rate substantially proportional to thefluid flow rate in the fluid-activated means,

means for dispensing the particulate material drawn from the bed,

a conduit connecting the fluid-activated means to the means fordispensing the particulate material, and

a fluid divider including an inlet port adapted to be connected to afluid under pressure, at least two outlet ports and a fluid impedancemeans adjacent the outlet ports, one of the outlet ports connected tothe fluid-activated means so as to provide fluid flow to thefluid-activated means from the fluid source, another of the outlet portsconnected to the conduit so as to provide a fluid flow in the conduitassisting in the movement of the particulate material in the conduittoward the means for dispensing the particulate material, the fluidimpedance means displaceable toward one of the outlet ports and awayfrom the other outlet port for predeterrninately dividing the fluid flowat the inlet port between the outlet ports whereby the fluid flow rateto the fluid activated is adjustable so as to withdraw variable amountsof particulate material from the bed without effecting the flow rate offluid in the conduit 14. The apparatus as claimed in claim 13, whereinthe fluid flow rate to the dispensing means is substantially constantand independent of the adjustment of the fluid divider.

15. The apparatus as claimed in claim 13 wherein the particulatematerial includes a powdery substance capable of being electrostaticallycharged and wherein the dispensing means includes an electrostatic spraygun capable of electrostatically charging the powdery substance.

16. The apparatus as claimed in claim 15, wherein the fluidactivatedmeans includes a fluidized bed containing the powdery substance and afluid-actuated pump which draws the powdery substance from the fluidizedbed at a rate proportional to the fluid flow rate through the pump.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,625,404 DatedM Inventor(s) Richard 0, Probgj:

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 5, line 30, after "encouraging", insert or discouraging Colunn 6,line 5, "ate" should read rate line 42, after "respect to", insertchamfer 44. After initial positioning and locking in place of themembers with respect to Column 8, line 4, "as" should read a line 63,"port" should read ports Column 9, line 46, "would" should read shouldColumn 10, line 48, "2" should read 20 Signed and sealed this 31st dayof October 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents FORM P0405) USCOMM-DC scan-ps9 ll 5 GOVERNMENT 'RINTINGOFFICE I915 0-3664.

1. An apparatus capable of dispensing particulate material comprising, abed containing particulate material, a fluid-activated means capable ofcausing the particulate material to be drawn from the bed at a ratesubstantially proportional to the fluid flow rate in the fluid-activatedmeans, means for dispensing the particulate material drawn from the bed,a conduit connecting the fluid-activated means to the means fordispensing the particulate material, and a fluid divider having an inletport connected to a source of fluid under an elevated pressure andhaving a plurality of outlet ports, one of the outlet ports cOnnected tothe fluidactivated means providing the fluid flow in the fluid-activatedmeans, another of the outlet ports connected to the conduit to provide afluid flow in the conduit which assists in the movement of theparticulate material in the conduit toward the means for dispensing theparticulate material, and the fluid divider including means activated bya fluid control signal thereby regulating the flow of fluid from atleast one of the outlet ports of the fluid divider so that the sum ofthe fluid flows at the outlet ports of the fluid divider issubstantially proportional to the fluid flow at the inlet port of thefluid divider.
 2. The apparatus as claimed in claim 1 wherein the fluiddivider includes a plurality of fluid regulators capable of adjustablyregulating the fluid flow rate supplied to the fluid-activated means andto the other outlet.
 3. The apparatus as claimed in claim 2 wherein atleast one of the fluid regulators is activated by the control signal tothereby adjustably regulate the fluid flow rate.
 4. The apparatus asclaimed in claim 1, wherein the particulate material includes a powderysubstance capable of being electrostatically charged and wherein thedispensing means includes an electrostatic spray gun capable ofelectrostatically charging the powdery substance.
 5. The apparatus asclaimed in claim 4, wherein the fluid-activated means includes afluidized bed containing the powdery substance and a fluid-actuated pumpwhich draws the powdery substances from the fluidized bed at a rateproportional to the fluid flow rate through the pump.
 6. A method fordispensing particulate material comprising dividing a fluid flow into aplurality of fluid flow outputs by means of a fluid divider activated bya fluid control signal thereby regulating the flow of fluid from thefluid divider, supplying one of the fluid flow outputs to afluid-actuated means capable of drawing particulate material from a bedat a rate proportional to the fluid flow rate in the fluid-activatedmeans, and combining the fluid flow rates from the fluid-activated meansand from another of the fluid flow outputs in a conduit connected to adispensing means whereby the fluid flow rate supplied to the dispensingmeans is substantially constant.
 7. In an apparatus for dispensingparticulate material, means for dividing a gaseous input into aplurality of gaseous outputs the sum of which is substantially equal tothe gaseous input to the means, one of the gaseous outputs is connectedto a particulate material-dispensing means and other of the gaseousoutputs is connected to the dispensing means through a source ofparticulate material, the dispensing means having a substantiallyconstant gaseous flow therethrough that is substantially independent ofthe particulate material dispensed whereby accumulation of particulatematerial in the apparatus is discouraged, the means for dividing thegaseous flow comprising a body including an inlet port and a pluralityof outlet ports connected by a bore, the inlet port adapted to beconnected to a gaseous medium source, the outlet ports connected to theparticulate material dispensing means, and a displaceable gaseousflow-splitting member in the bore of the body adjacent the outlet ports,the gaseous flow-splitting member displaceable toward one of the outletports and away from the remaining outlet ports thereby providing gaseousoutputs the sum of which is substantially equal to the gaseous input. 8.The means as claimed in claim 7, wherein the gaseous flow-splittingmember includes surfaces which encourage fluid flow toward the outletports.
 9. The means as claimed in claim 8, wherein the gaseousfluid-splitting member includes a plurality of frustoconical membershaving adjacent bases.
 10. The means as claimed in claim 9, wherein eachof the frustoconical members have substantially the same dimensions andsubstantially the same taper angle and each of the outlet ports havesubstantially eqUal area openings adjacent the frustoconical members.11. The means as claimed in claim 10, wherein the outlet ports are twooutlet ports spaced from each other and the openings thereof aresubstantially coaxial.
 12. The means as claimed in claim 11, wherein theaxis of the inlet port is substantially perpendicular to the axis of theoutlet ports.
 13. An apparatus for dispensing particulate materialcomprising a bed containing particulate material, a fluid-activatedmeans in the bed for causing the particulate material to be drawn fromthe bed at a rate substantially proportional to the fluid flow rate inthe fluid-activated means, means for dispensing the particulate materialdrawn from the bed, a conduit connecting the fluid-activated means tothe means for dispensing the particulate material, and a fluid dividerincluding an inlet port adapted to be connected to a fluid underpressure, at least two outlet ports and a fluid impedance means adjacentthe outlet ports, one of the outlet ports connected to thefluid-activated means so as to provide fluid flow to the fluid-activatedmeans from the fluid source, another of the outlet ports connected tothe conduit so as to provide a fluid flow in the conduit assisting inthe movement of the particulate material in the conduit toward the meansfor dispensing the particulate material, the fluid impedance meansdisplaceable toward one of the outlet ports and away from the otheroutlet port for predeterminately dividing the fluid flow at the inletport between the outlet ports whereby the fluid flow rate to the fluidactivated is adjustable so as to withdraw variable amounts ofparticulate material from the bed without effecting the flow rate offluid in the conduit
 14. The apparatus as claimed in claim 13, whereinthe fluid flow rate to the dispensing means is substantially constantand independent of the adjustment of the fluid divider.
 15. Theapparatus as claimed in claim 13 wherein the particulate materialincludes a powdery substance capable of being electrostatically chargedand wherein the dispensing means includes an electrostatic spray guncapable of electrostatically charging the powdery substance.
 16. Theapparatus as claimed in claim 15, wherein the fluid-activated meansincludes a fluidized bed containing the powdery substance and afluid-actuated pump which draws the powdery substance from the fluidizedbed at a rate proportional to the fluid flow rate through the pump.